Moving body tracking system, moving body tracking method, and program

ABSTRACT

A moving body tracking system, comprising: a first camera that captures image(s) of moving body entering an intersection, a plurality of second cameras installed in a plurality of locations set as destinations of the moving body entering the intersection, a moving direction determining part that determines a moving direction of the moving body entering the intersection due to a change in direction of the moving body based on captured data by the first camera, and a path specifying part that selects the second camera based on the moving direction of the moving body, searches a frame in which the specified moving body was captured from captured data by the second camera, and specifies a path of the moving body.

This application is a National Stage Entry of PCT/JP2019/034824 filed onSep. 4, 2019, which claims priority from Japanese Patent Application2018-165566 filed on Sep. 5, 2018, the contents of all of which areincorporated herein by reference, in their entirety.

FIELD Description of Related Applications

This application is based upon and claims the benefit of the priority ofJapanese patent application No. 2018-165566 filed on Sep. 5, 2018, thedisclosure of which is incorporated herein in its entirely by referencethereto.

The present invention relates to a moving body tracking system, a movingbody tracking method, and a program.

BACKGROUND

Origin-Destination (OD) surveys have been conducted as basic data forformulating road improvement plan and urban development plan. Forexample, the Ministry of Land, Infrastructure, Transport and Tourism(MLIT) conducts a nationwide OD survey every five years.

Patent Literature 1 discloses an automatic traffic volume measurementapparatus and an automatic traffic volume measurement system that canautomatically measure moving object and consolidate the measurementresults. According to the literature, this automatic traffic volumemeasurement apparatus comprises a moving object detection means, whichcompares a still image of a frame of video captured by a video camerawith a reference image that serves as a comparison basis, and detectsthe presence of the moving object in the still image according to thecomparison results. This automatic traffic volume measuring apparatusfurther comprises a type identifying means, which identifies the type ofthe moving object based on the pixels area of the image detected as themoving object by the moving object detecting means. This automatictraffic volume measurement apparatus further comprises a speedcalculating means, which calculates the moving speed of the movingobject based on the number of consecutive pluralities of the stillimages in which the presence of the moving object has been detected bythe moving object detecting means. This automatic traffic measurementapparatus further comprises a data generating means to generatedescriptive data that describes the images captured by the video camerain association with at least the type of the moving object, its movingspeed, and the time at which it was detected.

Patent Literature 2 discloses a traffic information management apparatusthat is capable of accurately and efficiently tracking a particularvehicle traveling on a road. According to this document, the trafficinformation management apparatus comprises traffic informationcollection apparatuses 200 a to f, which are formed of cameras and otherapparatuses installed at multiple points P1 to P6 on the road. By way ofrespective traffic information collection devices detecting the size,color, and other features of vehicles, the travel time(s) T1 to T5between respective apparatuses is estimated. Based on the estimatedtravel time(s), the arrival time(s) of the particular vehicle atrespective points are predicted, and the particular vehicle is detectedat the predicted time(s). This improves the detection accuracy of thespecific vehicle.

Patent Literature 3 discloses a traffic flow measurement apparatus thatis capable of not decreasing recognition accuracy even if some or all ofthe vehicles are not detected. According to the same document, thistraffic flow measurement apparatus comprises a location correction means24 that extracts vehicle candidates from the image data at time t andcorrects the position of the vehicle candidates whose mapping to time(t−1) has been completed using a predicted position. This traffic flowmeasurement apparatus also comprises a vehicle candidate correctionmeans 25 that adds vehicle(s) that failed to be extracted to the vehiclecandidates by giving their predicted position(s). This traffic flowmeasurement apparatus also comprises a passing judgment means 26 thatdetermines vehicle candidate(s) that does not exist in a predeterminedarea as passing vehicle(s), and calculates traffic information by takinginto account the location correction or addition of vehicle candidate(s)and passing vehicle(s).

-   [Patent Literature 1] Japanese Patent Kokai Publication No.    JP2005-4426A-   [Patent Literature 2] Japanese Patent Kokai Publication No.    JP2000-353290A-   [Patent Literature 3] Japanese Patent Kokai Publication No.    JPH08-147591A

SUMMARY

The following analysis is given by the present invention. The OD surveyas mentioned above has problems of being costly and time-consumingbecause it also uses questionnaires in combination. On the other hand,various devices have been proposed to identify moving bodies, such aspeople and vehicles, from images captured by cameras and other devices,and the accuracy of these devices has been improved (see PatentLiteratures 1-3). However, the automatic traffic measurement device ofPatent Literature 1 has the problem that it can only obtain descriptivedata (description data) at the location where the video camera isinstalled. This is also the case with Patent Literature 3, which aims atmeasuring traffic flow using a camera that takes pictures of the road inthe moving direction of a vehicle on the road.

The configuration of Patent Literature 2 does not bear in mind trackingof vehicles turning right or left, and to do so would require theinstallation of a large number of cameras along the presumed movingdirection of the vehicles, which would be costly.

It is an object of the present invention to provide a moving bodytracking system, a moving body tracking method and a program, whichenable to contribute to reducing the cost and survey time required fortracking moving bodies such as vehicles entering an intersection.

According to a first aspect of the invention, there is provided a movingbody tracking system, comprising: a first camera that captures image(s)of moving body entering an intersection, a plurality of second camerasinstalled in a plurality of locations set as destinations of the movingbody entering the intersection, a moving direction determining part thatdetermines a moving direction of the moving body entering theintersection due to a change in direction of the moving body based oncaptured data by the first camera, and a path specifying part thatselects the second camera based on the moving direction of the movingbody, searches a frame in which the specified moving body was capturedfrom captured data by the second camera, and specifies a path of themoving body.

According to a second aspect of the invention, there is provided amoving body tracking method, comprising: determining a moving directionof a moving body entering an intersection based on a captured data by afirst camera capturing the moving body entering the intersection, andselecting a second camera from a plurality of cameras installed in aplurality of locations determined as destinations of the moving bodyentering the intersection based on the moving direction of the movingbody, and specifying a moving path of the moving body by searchingframe(s) in which the moving body is captured from the captured data ofthe second cameras.

According to a third aspect of the invention, there is provided aprogram for causing a computer that is capable of accessing captureddata captured respectively, by a first camera that captures an image(s)of a moving body entering an intersection, and a plurality of secondcameras installed in a plurality of locations determined as destinationsof the moving body entering the intersection, to perform: a process thatdetermines a path direction of the moving body entering the intersectionbased on the captured data by the first camera, and a process thatselects the second camera based on a path direction of the moving body,and specifies a path of the moving body by searching a frame(s) in whichthe moving body is captured from the captured data of the second camera.It is to be noted that this program can be recorded on acomputer-readable (non-transient) storage medium. That is, the presentinvention can be implemented as a computer program product.

According to the present invention, it is possible to provide a movingbody tracking system, a moving body tracking method, and a program,which contribute to reducing the cost and time required to track andinvestigate moving bodies such as vehicles entering an intersection.That is, the present invention transforms the configuration for trackingand surveying moving bodies described in the background technology intoa configuration that is significantly improved in terms of its cost andsurvey time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram showing a configuration of an example embodiment ofthe present invention.

FIG. 2 is a diagram showing a description of an operation of an exampleembodiment of the present invention.

FIG. 3 is a diagram showing a description of an operation of an exampleembodiment of the present invention.

FIG. 4 is a diagram showing a configuration of a moving body trackingsystem according to a first example embodiment of the present invention.

FIG. 5 is a diagram showing an example of information stored in taggedand captured data storage part of a moving body tracking systemaccording to a first example embodiment of the present invention.

FIG. 6 is a diagram illustrating a function of an image tagging engine.

FIG. 7 is a diagram showing an example of information stored in movingbody path tracking data storage part of an example embodiment of thepresent invention.

FIG. 8 is a flowchart showing an operation of moving body trackingsystem of an example embodiment of the present invention.

FIG. 9 is a diagram showing a description the tracking operation of themoving body by the moving body tracking system of a first exampleembodiment of the present invention.

FIG. 10 is a diagram showing a configuration of a moving body trackingsystem according to a second example embodiment of the presentinvention.

FIG. 11 is a diagram showing an example of a path display by the secondexample embodiment of the present invention.

FIG. 12 is a diagram showing a configuration of a computer formulating amoving body tracking system according to the present invention.

PREFERRED MODES

First, an outline of one mode of this invention will be described withreference to the drawings. Reference numbers referring to the drawingsmentioned in this outline are for convenience as an example forfacilitating understanding, and not intended to limit the presentinvention to the illustrated modes. And respective connection line(s)between blocks in the reference drawing appearing in the followingdescription includes both bi-directional and single-directional. Asingle-directional arrow describes a main data flow schematically,which, however, does not exclude bidirectionality. In the followingdescription, “A and/or B” is used in the sense of A and B, or A or B.The program is executed via a computer apparatus, and the computerapparatus is equipped with, for example, a processor, a storage device,an input device, a communication interface, and a display device ifnecessary. The computer apparatus is also configured to be able tocommunicate with devices (including computers) inside or outside thedevice via the communication interface, irrespective of wired orwireless. In the following description, “A and/or B” is used in thesense of at least one of A and B.

In one example embodiment thereof, the present invention can be realizedby a moving body tracking system 20A that includes a first camera 11, aplurality of second cameras 12A, 12B, a moving direction determiningpart 21, and a path specifying part 22, as shown in FIG. 1. Moreconcretely, the first camera 11 captures an image(s) of a moving bodyentering an intersection (e.g., intersection A in FIG. 1). The secondcameras 12A and 12B are installed in a plurality of locations asdestinations for the moving body entering the intersection and capturean image(s) of the moving body passing through the intersection.

Based on the captured data of the first camera 11, the moving directiondetermining part 21 determines the moving direction of the moving bodydue to a change in direction of the moving vehicle entering theintersection. For example, as shown in FIG. 2, when a vehicle V entersan intersection A and turns right, the moving direction detecting part21 determines that the vehicle V has turned right based on the captureddata of the first camera 11.

Then, the path specifying part 22 selects the second camera 12A based onthe moving direction of the moving body, and identifies the moving pathof the moving body by searching (in) the frame in which the identifiedmoving body has been captured from the captured data of the secondcamera 12A. For example, as shown in FIG. 3, when the path specifyingpart 22 confirms the movement of a vehicle whose identificationinformation (CAR) is 42 from the captured data of the second camera 12A,it determines that the vehicle has moved from the intersection A to aLocation B1 where the second camera 12A is installed. By repeating thesame kind of processing, it is possible to track a moving body thatmoves through multiple sections.

In this way, the moving body tracking system 20A identifies the path ofa moving body such as a vehicle that has entered an intersection. As isclear from the above description, the moving direction determining part21 determines the moving direction of the moving body, and the pathspecifying part 22 selects the second camera based on this movingdirection. This makes it possible to reduce the number of camerasinstalled and to track the moving body efficiently, thereby reducingcosts and investigation time.

First Example Embodiment

Then, a first example embodiment of the present invention applied to ODsurvey will be described in detail with reference to the drawings. FIG.4 shows a configuration of a moving body tracking system according tothe first example embodiment of the present invention. Referring to FIG.4, a configuration is shown including a plurality of cameras 10, animage tagging engine 40, a tagged captured data storage part 50, amoving body tracking system 20, and a moving body path data storage part60.

A plurality of cameras 10 are placed, one at respective intersection ofthe area to be surveyed for OD. Respective camera 10 is located at aposition that can capture images of a moving body entering theintersection from the front, rear, left and right directions, andidentify the moving direction of the moving body entering theintersection from respective directions. For intersections equipped withtraffic lights, the power supplied to the traffic lights can be used asa power source for these cameras 10. Appropriate locations forinstallation of the cameras 10 are selected depending on theintersection conditions and the focal length of the lens to be mounted.In this example embodiment, these cameras 10 will function as the firstand second cameras described above.

It is preferable that the cameras 10 are of a portable type. By doingso, it is possible to bring the cameras 10 to the area where the ODsurvey is to be conducted, install the cameras 10 at the necessarylocations, and conduct the survey, thereby allowing further reduction ofthe cost of the survey.

An image tagging engine 40 is connected to respective cameras 10 via thenetwork 30, and analyzes the captured data taken by respective camera(s)10 to recognize and tag the object(s) in the captured data. Anin-vehicle recognition device can be used as such an image taggingengine 40. The captured data tagged by the image tagging engine 40 isstored in the tagged captured data storage part 50.

A tagged captured data storage part 50 stores the tag informationcreated by the image tagging engine 40 along with the captured data.

FIG. 5 shows an example of information held in the tagged captured datastorage part 50. The example in FIG. 5 shows tag information with thefollowing parameters: object ID, frame number, box coordinate1, boxcoordinate2, object type, captured time, and camera locationinformation.

An example of the operation of the image tagging engine 40 will now beexplained. FIG. 6 shows an example of the captured data input to theimage tagging engine 40.

Step P1: The image tagging engine 40 extracts object(s) such asvehicle(s), bicycle(s), person(s), etc., from the captured data and addsa rectangular frame (also called as bounding box). The image taggingengine 40 extracts object(s) such as vehicle(s), bicycle(s), person(s),etc., and assigns an ID (object ID) to respective detected object(s).The image tagging engine 40 obtains the captured date and time, framenumber, and location information of the camera (camera locationinformation) of the captured data. These can be obtained from themetadata annexed to the captured data.

Step P2: The image tagging engine 40 acquires coordinates of the upperleft corner (x1, y1) and lower right corner (x2, y2) of the rectangularframe (bounding box) when the upper left corner of the image is set asthe origin (0, 0) for the rectangular frame. These coordinatescorrespond to the box coordinates 1 and 2 in FIG. 5. Box coordinates 1and 2 make it possible to grasp (determine) the size of the object andits distance from the camera.

Step P03: The image tagging engine 40 determines whether the objectextracted above is a vehicle, a bicycle or a person. The result of thisdetermination becomes the object type information shown in FIG. 5. Theobject type can be determined using various methods, for example, bycalculating the degree of similarity with predetermined standard objectimage(s), or by using AI (Artificial Intelligence). In thisdetermination process, in case where the accuracy of the object type isobtained, it may be included in the tag information of the accuracy.

In this way, respective information shown in FIG. 5 can be obtained. Theabove operations of the image tagging engine 40 and the tag informationin FIG. 5 are only examples, and various changes can be made. Forexample, if license plate (“number plate”) information of a vehicle isobtained, it is possible to use the license plate number as an object IDof the vehicle.

The moving body tracking system 20 identifies the path of the movingbody using the captured data and tag information stored in theabove-tagged captured data storage part 50, and stores it in the movingbody path data storage part 60.

More concretely, the moving body tracking system 20 has a trackingtarget selecting part 23, a moving direction determining part 21, aspeed estimation part 24, and a path specifying part 22.

When the object ID to be tracked is input, the tracking target selectingpart 23 reads the data with the corresponding object ID from the taggedcaptured data storage part 50 and sends it to the moving directiondetecting part 21.

The moving direction detecting part 21 selects the frame with the oldestcaptured time and the frame with the newest captured time of the taginformation exemplified in FIG. 5, and determines the moving directionof the moving body according to a change(s) in box coordinates 1 and 2.For example, if both the X and Y coordinates change significantly, themoving direction determining part 21 determines that the moving body(vehicle) has made a right or left turn at the intersection. On theother hand, if only one of the X and Y coordinates is changingsignificantly, the moving direction detecting part 21 determines thatthe moving body (vehicle) is running straight through the intersection.The moving direction detecting part 21 sends the object ID and theresult of the determination to the speed estimating part 24.

The speed estimating part 24 selects a frame with an oldest capturedtime and a frame with a newest captured time of the tag informationexemplified in FIG. 5, and calculates a moving distance of the movingbody by changing the box coordinates' and 2. Next, the speed estimatingpart 24 calculates the speed of the moving body by dividing thecalculated distance traveled by the difference in the captured times.The speed estimating part 24 sends the object ID and its estimated speedas a result of the determination to the path specifying part 22.

The path specifying part 22 calculates an intersection that the movingbody is assumed to pass through next and its estimated arrival timebased on the moving direction and estimated speed obtained by the movingdirection detecting part 21 and speed estimating part 24, and theconnection relationship between intersections. Then, the path specifyingpart 22 reads out the captured data of the estimated arrival time fromthe captured data taken by the camera 10 that is captured thecorresponding intersection. If any object similar to an objectidentified by the object ID is captured in the read data, the pathspecifying part 22 determines that it is the same moving body andrecords it as the moving path of the corresponding object ID.

Repeating the above operation, the moving body tracking system 20creates the path information of the moving body and stores it in themoving body path data storage part 60.

FIG. 7 shows an example of the path information held in the moving bodypath data storage part 60. The example in FIG. 7 shows the pathinformation of a moving body, which is configured by sequentialrecording of its passing location for respective object ID and itscaptured time.

Next, the operation of this example embodiment will be described indetail with reference to the drawings. FIG. 8 is a flowchartrepresenting the operation of the moving body tracking system accordingto the first example embodiment of the present invention. Referring toFIG. 8, first, the moving body tracking system 20 selects a moving bodyto be tracked, starting from an arbitrary point (step S001). Thisselection of the moving body to be tracked may be instructed by theuser, or it may be an object ID selected by the moving body trackingsystem 20. For example, a scheme in which the moving body trackingsystem 20 tracks all of the object IDs detected at any given location byreferring to the tagged captured data storage 50 can also be adopted.

Next, the moving body tracking system 20 determines the moving directionof the moving body having the selected object ID (Step S002).

Next, the moving body tracking system 20 estimates a speed of the movingbody having the selected object ID (Step S003).

Next, the moving body tracking system 20 identifies a path by referringto the data of the captured time obtained from the estimated speed inthe captured data of the intersection to which the moving body havingthe selected object ID is moving (Step S004).

And next, the moving body tracking system 20 determines whether or notthe tracking of the moving body having the selected object ID should beterminated (Step S005). The conditions for terminating the tracking ofthe moving body may be as follows. The first condition is when themoving body being tracked reaches an intersection at the end of the areain which the OD survey is conducted. In this case, the tracking can beterminated because the identification of the starting point, the endingpoint, and the path between them has been completed. The secondcondition is when loss of sight of the moving body under tracking hasoccurred. In this case, the reason may be that the moving body hasstopped moving from the last intersection, for example, because it hasreached its destination. In this case, too, the identification of thestarting point, the end point, and the path between them has beencompleted, so the tracking can be terminated. Another reason for losingsight of the moving body under tracking is that the moving body made aU-turn in the middle of the road, and the tracking has failed. In thiscase, the survey may be terminated, or the search may be continued byexpanding the search target.

If, as a result of the above determination, it is determined thattracking is to be continued (NO in step S005), the moving body trackingsystem 20 reads the captured data of the intersection which thecorresponding moving body last entered and continues the processing ofsteps S002 to S004.

On the other hand, if it is determined that the tracking is to beterminated (YES in step S005), the moving body tracking system 20records the path information exemplified in FIG. 7 in the moving bodypath data storage part 60, and ends the processing.

With reference to FIG. 9, the operation of the moving body trackingsystem 20 of this example embodiment will be described in detail. In thefollowing explanation, it will be assumed that an OD survey of a movingbody originating from Location A is performed. For example, let usassume that a vehicle with object ID=42 passed Location A at 9:34:20(hour:minute:second). In this case, the moving body tracking system 20estimates that the vehicle with object ID=42 is destined to Location Bbased on the captured data at Location A, and that an estimated time ofarrival is 9:34:30.

Next, based on the moving direction determined at Location A and theestimated time of arrival, the moving body tracking system 20 identifiesa vehicle that passed Location B at around 9:34:30 among the captureddata at Location B. In the example in FIG. 9, the vehicle with objectID=42 and a vehicle ID with object ID=130 are shown (captured), but themoving body tracking system 20 selects the vehicle with object ID=42,which has a more similar appearance. Then, the tracking system 20selects the vehicle with the object ID=42 based on the captured data atLocation B.

In the similar way, the moving body tracking system 20 identifies thevehicle that passed Location C at around 9:34:40 among the captured dataat Location C based on the moving direction determined at Location B andthe estimated time of arrival. In the example in FIG. 9, the vehiclewith object ID=42 and a vehicle with object ID=10 are shown, but themoving body tracking system 20 selects the vehicle with object ID=42,which has a more similar appearance. In the same way below, the movingbody tracking system 20 confirms that the vehicle with object ID=42 hasreached Location D, at which it ends the tracking.

As explained above, according to this example embodiment, it is possibleto track a moving body by installing one or more cameras perintersection. The reason for this is that the moving body trackingsystem 20 has adopted a configuration to determine the moving directionand thereby track the moving body. This system also makes it possible toreduce the investigation time. The reason for this resides in that themoving body tracking system 20 estimates the speed of the moving bodyand uses the estimated arrival time of the moving body to efficientlyconduct tracking. Note, the moving bodies do not necessarily pass onlythe intersections at which the cameras are installed, and it is possiblethat a certain number of moving bodies may be lost from tracking, asdescribed in step S005 above. However, the collection rate ofquestionnaires in the current OD survey is about 30 to 60% (conducted bythe MLIT in fiscal year 2015), and the survey data can be sufficientlyobtained with this method, too.

Second Example Embodiment

Next, a second example embodiment, which uses the configuration of thefirst example embodiment above and adds a function of displaying mapinformation representing a path of a particular moving body, will bedescribed in detail with reference to the figures. FIG. 10 shows aconfiguration of the second example embodiment of the moving bodytracking system. Referring to FIG. 10, a configuration in which aselection accepting and responding part 25 is added to the moving bodytracking system 20B is shown.

The selection accepting and responding part 25 comprises a function todisplay map information on a predetermined map that displays a movementpath of a moving body accepted from a predetermined user terminal.Concretely, when the selection accepting and responding part 25 receivesa selection of a moving body from a predetermined user terminal, ittakes out (retrieves) path information of the corresponding object IDfrom the moving body path data storage part 60. Then, the selectionaccepting and responding part 25 responds, to the user terminal, mapinformation displaying a movement path of the moving body whoseselection was accepted on a predetermined map.

FIG. 11 shows an example of a path display mode of a moving bodytracking system by the second example embodiment of the presentinvention. For example, it is assumed that the selection accepting andresponding part 25 accepts a designation of the vehicle with objectID=42 from a predetermined user terminal.

In this case, the moving body tracking system retrieves the pathinformation of an object with object ID=42 from the moving body pathdata storage 60. The user terminal displays map information showing themoving path of the object with object ID=42 on a predetermined map, asshown in FIG. 11.

The user of the user terminal can check a movement history of suspiciousvehicle(s) by referring to such map information. Of course, it is alsopossible to specify a moving body other than a vehicle as an object IDand check (monitor) its movement history. For example, it is possible totrack a bicycle(s) used by a criminal person to escape, which can beuseful for criminal investigations.

As described above, this invention can be used not only as an OD surveybut also as a tracking system (displaying movement history) specifyingany vehicle.

Although the respective example embodiments of the present inventionhave been described above, the present invention is not limited to theabove-described example embodiments, and further modifications,replacements, and adjustments can be made without departing from thebasic technical concept of the present invention. For example, thenetwork configuration, the configuration of respective elements, and theexpression form of the message(s) shown in respective drawings areexamples for helping understanding of the present invention, and are notlimited to the configurations shown in these drawings.

In addition, the procedure(s) shown in the above-described first tosecond example embodiments can be realized (implemented) as a programfor causing a computer (9000 in FIG. 16) that functions as the movingbody tracking system 20/20A/20B to execute processing as the moving bodytracking system. For example, this kind of computer has a configurationcomprising Central Processing Unit (CPU) 9010, Communication Interface9020, Memory 9030, and Auxiliary Storage Device 9040 as described inFIG. 12. That is, the CPU 9010 of FIG. 12 executes the moving directiondetermining program/speed estimating program, the data conversionprogram and refers to the calculating parameters held in the auxiliarystorage device 9040 to execute the processing.

That is, every part (processing means, function) of moving body trackingsystem described in first and second example embodiments can be realizedby a computer program that causes the processor in these systems toexecute above processing using its hardwares respectively.

Lastly, preferred modes of the present invention are outlined hereinbelow.

[Mode 1]

(Refer to above mentioned moving body tracking system of the firstaspect of the present invention.)

[Mode 2]

The moving body tracking system, further comprising a speed estimatingpart that estimates a speed of the moving body based on a location ofthe moving body recorded in the captured data by the first camera,wherein the path specifying part selects the captured data by the secondcamera based on the speed of the moving body.

[Mode 3]

The moving body tracking system, wherein the cameras are installed in anintersection of an area in which an Origin-Destination (OD) survey isconducted, and the system comprises a function that performs the ODsurvey by causing the cameras to function as the first and/or secondcamera(s).

[Mode 4]

The moving body tracking system, wherein the first camera is installedat a location that allows to capture the moving body entering theintersection, from the front, back, left and right directions, andidentify the moving direction of the moving body entering theintersection, from respective direction.

[Mode 5]

The moving body tracking system, further comprising: a path storage partthat stores path information indicating a path for respective identifiedmoving body, and a map information displaying part that displays mapinformation displaying a path of the moving body accepted from apredetermined user terminal on a predetermined map.

[Mode 6]

(Refer to above mentioned moving body tracking method of the secondaspect of the present invention.)

[Mode 7]

(Refer to above mentioned program of the third aspect of the presentinvention.)

Mode 6 and Mode 7 can be expanded to Modes 2 to 5 likewise as the Mode1.

It is to be noted that each of the disclosures in the abovementionedpatent literatures is incorporated herein by reference. Modificationsand adjustments of example embodiments and examples are possible withinthe bounds of the entire disclosure (including the claims) of thepresent invention, and also based on fundamental technologicalconcept(s) thereof. Furthermore, a wide variety of combinations andselections (including partial deletions) of various disclosed elementsis possible within the scope of the claims of the present invention.That is, the present invention clearly includes every type oftransformation and modification that a person skilled in the art canrealize according to the entire disclosure including the claims and totechnological concept(s) thereof. In particular, with respect to thenumerical ranges described in the present application, any numericalvalues or small ranges included in the ranges should be interpreted asbeing specifically described even if not otherwise explicitly recited.

SIGNS LIST

-   10 Camera-   11 First camera-   12A, 12B Second cameras-   20, 20A, 20B Moving body tracking system-   21 Moving direction determining part-   22 Path specifying part-   23 Tracking target selecting part-   24 Speed estimating part-   25 Selection accepting and responding part-   30 Network-   40 Image tagging engine-   50 Tagged captured data storage part-   60 Moving body path data storage part-   9000 Computer-   9010 CPU-   9020 Communication Interface-   9030 Memory-   9040 Auxiliary Storage Device-   V Vehicle

What is claimed is:
 1. A moving body tracking system, comprising: afirst camera that captures image(s) of moving body entering anintersection, a plurality of second cameras installed in a plurality oflocations set as destinations of the moving body entering theintersection, a memory configured to store instructions, and a processorconfigured to execute the instructions, the instructions comprising:determining a moving direction of the moving body entering theintersection due to a change in direction of the moving body based oncaptured data by the first camera, and selecting the second camera basedon the moving direction of the moving body, searches a frame in whichthe specified moving body was captured from captured data by the secondcamera, and specifies a path of the moving body.
 2. The moving bodytracking system according to claim 1, further comprising estimating aspeed of the moving body based on a location of the moving body recordedin the captured data by the first camera, and selecting the captureddata by the second camera based on the speed of the moving body.
 3. Themoving body tracking system according to claim 1, wherein the camerasare installed in an intersection of an area in which anOrigin-Destination (OD) survey is conducted, and the system comprisesperforming the OD survey by causing the cameras to function as the firstand/or second camera(s).
 4. The moving body tracking system according toclaim 1, wherein the first camera is installed at a position that allowsto capture the moving body entering the intersection, from the front,back, left and right directions, and identify the moving direction ofthe moving body entering the intersection, from respective direction. 5.The moving body tracking system according to claim 1, furthercomprising: storing path information indicating a path for respectiveidentified moving body, and displaying map information displaying a pathof the moving body accepted from a predetermined user terminal on apredetermined map.
 6. A moving body tracking method, comprising:determining a moving direction of a moving body entering an intersectionbased on a captured data by a first camera capturing the moving bodyentering the intersection, and selecting a second camera from aplurality of cameras installed in a plurality of locations determined asdestinations of the moving body entering the intersection based on themoving direction of the moving body, and specifying a moving path of themoving body by searching frame(s) in which the moving body is capturedfrom the captured data of the second cameras.
 7. The moving bodytracking method according to claim 6, further comprising: estimating aspeed of the moving body based on a location of the moving body recordedin the captured data by the camera, and selecting the captured data bythe second camera based on the speed of the moving body.
 8. Acomputer-readable, non-transient recording medium storing a program forcausing a computer that is capable of accessing captured data capturedrespectively, by a first camera that captures an image(s) of a movingbody entering an intersection, and a plurality of second camerasinstalled in a plurality of locations determined as destinations of themoving body entering the intersection, to perform: a process thatdetermines a path direction of the moving body entering the intersectionbased on the captured data by the first camera, and a process thatselects the second camera based on a path direction of the moving body,and specifies a path of the moving body by searching a frame(s) in whichthe moving body is captured from the captured data of the second camera.9. The moving body tracking method according to claim 6, wherein thecameras are installed in an intersection of an area in which anOrigin-Destination (OD) survey is conducted, and the method comprisesperforming the OD survey by causing the cameras to function as the firstand/or second camera(s).
 10. The moving body tracking method accordingto claim 6, wherein the first camera is installed at a position thatallows to capture the moving body entering the intersection, from thefront, back, left and right directions, and identify the movingdirection of the moving body entering the intersection, from respectivedirection.
 11. The moving body tracking method according to claim 6further comprising: storing path information indicating a path forrespective identified moving body, and displaying map informationdisplaying a path of the moving body accepted from a predetermined userterminal on a predetermined map.
 12. The medium according to claim 8,the program further comprising: estimating a speed of the moving bodybased on a location of the moving body recorded in the captured data bythe first camera, and selecting the captured data by the second camerabased on the speed of the moving body.
 13. The medium according to claim8, wherein the cameras are installed in an intersection of an area inwhich an Origin-Destination (OD) survey is conducted, and the programcomprises performing the OD survey by causing the cameras to function asthe first and/or second camera(s).
 14. The medium according to claim 8,wherein the first camera is installed at a position that allows tocapture the moving body entering the intersection, from the front, back,left and right directions, and identify the moving direction of themoving body entering the intersection, from respective direction. 15.The medium according to claim 8, the program further comprising: storingpath information indicating a path for respective identified movingbody, and displaying map information displaying a path of the movingbody accepted from a predetermined user terminal on a predetermined map.